An automated method for measuring chloride that generates silver ions in the reaction is which technique?

• A. Coulometry
• B. Mass Spectrometry
• C. Chromatography
• D. Polarography

Answer: (A)

Generating silver ions in the reaction is characteristic of Coulometry. In this method, a controlled current produces Ag+ electrochemically; these silver ions then react with chloride to form AgCl in a 1:1 stoichiometry. Since the amount of charge passed equals the amount of silver generated, you can calculate the chloride amount directly from the total coulombs measured, making Coulometry a precise, automated way to titrate chloride.

Mass spectrometry would detect ions or quantify them by mass-to-charge, not by a timed, stoichiometric reaction with silver. Chromatography separates components rather than performing a charge-driven titration. Polarography measures current versus potential to infer concentration but does not rely on generating silver ions to titrate chloride.